Our young brain, that of the homo-sapiens (“wise man” in Latin) is just about 100,000 years old. This newly evolved organ endows us with unique creative capabilities that no other living creature has. We invented spoken language and later writing (5000 years ago), art (30,000 years ago) and science (3500 years ago). We constantly develop new tools that overcome our physical limitations – telescopes (“far-seeing”), microscopes (“small-seeing”), airplanes, computers, cell phones, the Internet, to name but a few of the most obvious. In the last 100 years or so, the scientific discipline provided a dramatic new understanding of life itself (deciphering the human genome) and of the fundamental laws governing the universe (theory of relativity). Despite an explosive population growth, science has found new ways to increase our lifespan, which is expected to cross an average of 100 years during the 21st century.
Humans – having become conscious of the fact that they have a brain and that their very survival and success in life depends on utilizing its power – have begun to race to reverseengineer it, understand it and augment it. Towards this end, we are harnessing every trick in the book of mathematics, physics, chemistry, pharmacology, biology, psychology, as well as computer science, information sciences, and engineering – thus giving birth to the AugCog Era.
This cognitive terra incognita capacity of the human brain has remained largely unexploited for 100,000 years, “waiting” to be unraveled, exposed, “tapped-on.” These hard-to-foresee capabilities rely on the high dimensional states that our brain can generate; indeed, the brain uses hundreds of billions of neurons – as many as there are stars in our milky way galaxy – and 1000 trillion synapses to send billions of messages every second through its intense network (see the “Human Connectome Project”: http://www.humanconnectomeproject.org/). Most importantly, the human brain is probably the most plastic and adaptive device in the universe, constantly changing its network connectivity to enable new capabilities each time we face a personal challenges. Indeed, numerous studies over the last decades have shown that perception, cognition, behavior, memory, our very self, are constantly changing throughout life. But to change the brain in a way that we can enhance its full potential requires dedication, discipline and perseverance and long durations of training, as any athlete, pianist, mathematician, artist, or philosopher will tell you. It is becoming clear that our cognitive capabilities can also be changed rapidly, either by a powerful emotional event (traumatic or pleasant), or via the use of physical manipulations such as neural prosthetics devices and pharmaceuticals.
The new AugCog research field focuses on the development of scientifically-based rigorous genetic, pharmacological, electrical and optical devices, combined with brain-computer interfaces (BCI), for restoring and augmenting cognition (e.g., cochlear implants for restoring hearing or using deep brain stimulations in Parkinson’s disease. The effect of various drugs for restoring cognitive functions (e.g., in cases of post-traumatic stress disorders) are also studied and even the possibility of growing living in vitro brain structures and using them as external systems, linked telemetrically and bi-directionally to the patient’s brain, is explored A subfield of AugCog is the study of the relationship between basic operational states of the brain, such as sleep, as well as of daily activities such as dance or listening to music and their impact on augmenting cognitive capabilities. The AugCog research field has far-reaching ethical and philosophical implications. What are the principles that should guide us when using drugs and other methods for repairing the sick brain and for enhancing cognition in normal brains? In the last few years there has been a growing debate in the scientific and bioethical community about these issues. The public, scientists and governments have started to discuss the social, ethical and policy implications of cognitive-enhancing methods.
The future of human cognition. Chapter 6 raises an interesting question – are we all potential geniuses? Do we all have almost unlimited capabilities that are “buried” in our neuronal networks and that are only sometimes expressed in unique individuals, be it great geniuses (like Einstein or Picasso) or autistic savants? And if this is indeed the case, then how might we effectively access this buried potential? Or should we? We do so constantly when learning a new skill, when daring to take new routes and imagine the yet unknown. But on top of this ongoing naturally evolving cognitive capability, which we pass from one to the other via information technologies, we have entered the age where we can begin to augment cognition by directly probing the brain with modern technologies, both virtual and physical. We should use these new capabilities very carefully, as they could potentially change the essence of who we are.
What is clear is that we are already in the AugCog era, where direct manipulation of the brain’s activity can augment human cognition. The book Augmenting Cognition, edited by Idan Segev and Henry Markram, is the first summary of this incredible new chapter in human history.
The book came to life following the great interest generated by a special issue on the same topic published in the journal Frontiers in Neuroscience.
Sensory Stimulation for Augmenting Perception, Sensorimotor Behavior and Cognition
Heritable features evolving during evolutional time spans are of ultimate advantage for survival and are without exception structurally fixed. To cope successfully with the ongoing changes of environmental conditions occurring during the lifespan of individuals, additional mechanisms, allowing rapid and effective adaptations that are not specified by genetic constraints, are required.
Given these obvious needs for plastic adaptations, it appears only natural that brain plasticity of various forms corresponds to a general and ubiquitous feature present in all sensory and motor modalities. In this context, it is surprising that the notion of adult neuroplasticity has not established itself sooner than the late eighties of the last century. Before that, the neuroscience community conceived adult brains as being non-plastic.
Numerous studies over the last decades have shown that perception, behavior and cognition are not constant, but subjected to manifold modifications throughout a lifespan. Major determinants include development and aging as well as alterations following injury-related brain reorganization. Other sources modifying behavior originate from constraints arising under conditions of everydaylife, e.g., particularities of occupation including life-style and prolonged episodes of heavy schedules of sensory stimulation as exemplarily present in blind Braille readers or musicians. It should be emphasized that, in spite of the substantial amount of plastic capacities, systems must possess a sufficient generic stability to warrant secure processing. Conceivably, there is a trade-off between modifiability and stability.
The gold standard to achieve high-level skills is to undergo long periods of training. For example, it takes several tens of thousands of hours of intense practice to develop musical skills typically observed in professional musicians. Similar numbers also hold for other expert performances in for instance sports. The recent development of non-invasive imaging techniques has made it possible to analyze the impact of training and practice also in humans. These investigations have provided overwhelming evidence that extensive use and practice result in substantial changes of associated cortical representations thus confirming previous data from animal studies. As a result, a large community in neuroscience now deals with brain changes evoked by training and practice to determine properties and mechanisms of neuroplasticity.
Findings from such studies imply that almost every possible action/occupation/training affects brain organization. As a consequence, brains must be regarded as dynamically maintained throughout life. In a way, this makes brains similar to muscles: much usage causes them to expand, while poor use makes them shrink. The new message is that this not only holds for the developmental period, or for functional changes in adults, but also for structural changes during adulthood. So, anything one does leaves a trace in the brain. The dark side of that is that also everything one does not do leaves traces, which implies that the acquisition of skills and capabilities can hardly be maintained without practice. There is no freezing of skills, because the brain machinery underlying them will deteriorate if not active, which has a number of severe implications particularly crucial in the field of aging.
For several years, a new and fascinating discipline has evolved, where neuroscientists now successfully make use of neuroplasticity principles to induce what can be called targeted brain plasticity. This is done by means of protocols that do not rely on the conventional modification of use, training and practice. Instead, by targeting defined brain areas, either through sensory stimulation, or through direct stimulation of the brain (by means of transcranial magnetic stimulation), learning processes can be induced. While, at first glance, such approaches should not work at all, there is now evidence of an almost amazing efficacy, including improvements of simple motor and perceptual tasks, but also much more cognitively demanding abilities.
This chapter will provide a review of recent work where human behavior and perception has been modified through mere exposure, i.e., sensory stimulation protocols incorporating canonical protocols used to alter synaptic transmission and efficacy. In addition, we will briefly summarize alternative attempts based on sensory stimulation with the goal to improve human functions.
Electric cochlear stimulation
Cochlear prostheses have been used for many years to restore sound perception in patients with profound sensorineural deafness. By electrically stimulating acoustic nerve fibers, the central auditory system can be systematically activated to maintain the capacity for hearing. A first account of this approach can be traced back nearly half a century. When utilizing the critical period for speech acquisition, clinical data suggest that children implanted before 2 years of age have an excellent chance of acquiring speech understanding. Electrical implant stimulation does not rely on a perfect imitation of normal patterns of peripheral neural activity, but on a re-learning of input patterns arising from an artificial sensory input via electrical stimulation. In this sense, the ability for gaining/re-gaining speech understanding mediated by cochlear stimulation is accomplished by new strategies of cortical processing that serve higher processing stages to interpret new patterns arriving from the periphery. These strategies are thought to emerge from plastic capacities in response to the constraints imposed by the properties of the new input statistics that in turn result from the stimulation strategy employed.
Vagal nerve stimulation
Animal studies have shown that a pairing of sensory stimuli with electrical stimulation of the cholinergic nucleus basalis generates long-lasting changes in the cortical organization. However, as this form of intervention is highly invasive, it is not practical for clinical use. As vagal nerve stimulation triggers the release of neuromodulators known to promote plastic changes, it is a less invasive method for generating targeted neural plasticity by pairing vagus nerve stimulation with sensory inputs. Thereby, the efficacy of vagal nerve stimulation in enhancing plasticity seems to lie in the synergistic action of multiple neuromodulators acting in the cerebral cortex and other brain regions. In fact, it was recently demonstrated that in an animal model of tinnitus, where the auditory cortex was degraded by repeated exposure to intense noise, a repeated pairing of tones with brief pulses of vagus nerve stimulation completely eliminated the physiological and behavioral correlates of tinnitus in noise-exposed rats. This suggests that the approach might have potential clinical values.
Virtual reality and augmented reality devices
Virtual reality applications offer new opportunities to study not only brain activation under unusual stimulation conditions, but also for an enhancement of sensorimotor and cognitive functions in humans. Mobility impairment is a frequently encountered phenomenon often observed during aging or in association with neurological diseases such as Parkinson’s disease (PD) or multiple sclerosis (MS). Alternative to conventional rehabilitation by physiotherapy or medication, new attempts using closed-loop visual and auditory feedback provided through augmented reality or virtual reality devices have been shown to provide promising routes in the treatment of gait disorders.
Subjects have to wear a set of devices consisting of a small measurement-computation unit attached to the patient’s clothing, a headmounted microdisplay, and earphones. The measurement-computation unit is composed of a multiaxial accelerometer, a compass, and a microcontroller. The apparatus, operating in an adaptive closed-loop mode, displays a life-size virtual checkerboard-tiled floor superimposed on the real world by see-through glasses. The closed-loop or feedback concept implies that the speed of the cues is not externally set but is an outcome of the walking speed of the user. The visual effect is the same as that created when walking over earth-stationary cues such as a real tiled floor. Similarly, the rhythm of the auditory cue is determined by the rhythm of the steps, not vice versa.
The next stage involves the user regulating the gait pattern to create a constant optical flow and a rhythmic auditory cue. The virtual, augmented floor responds dynamically to the participant’s own motion and “moves” toward him at the speed set by the user as measured by the accelerometer. The tiled floor acts as a moving visual display whose speed is generated in a natural feedback fashion by its own motion. The grid allows the user to step on the tiles with long strides as they walk, though they do not become enlarged or modified based on previous step lengths. A steady gait synchronizes the patient’s own steps with the virtual tiles and the auditory cues, thus “rewarding” the user for making the effort. Additional auditory feedback from the patient’s own steps is provided through earphones. The auditory feedback is continuous so long as patients are walking steadily, producing a rhythm they hear based on their gait pattern.
This system has been successfully tested in PD and MS patients as well as in elderly individuals characterized by severe gaterelated gait impairments. Generally, most albeit not all users demonstrated improvements in walking velocity and stride length, which were maintained after device removal. Nevertheless, more studies are needed to understand the factors contributing to the overall compliance of the system. Independent of this, the use of closed-loop sensory feedback appears to be a new and effective intervention to improve gait and mobility without relying on medication.
Extracted from Augmenting Cognition
Edited by Idan Segev and Henry Markram
Published by The EPFL Press